US4812423AExpiredUtilityPatentIndex 88
Optical light weight glass
Est. expiryJan 27, 2004(expired)· nominal 20-yr term from priority
C03C 3/076C03C 3/087C03C 3/089Y10S501/903C03C 3/083
88
PatentIndex Score
27
Cited by
12
References
2
Claims
Abstract
This specification discloses optical light-weight glass having a composition of SiO2 47-70, Li2O 5.5-21, K2O 2-30, Na2O 0-30 (Li2O+Na2O+K2O 21-50), TiO2 9.5-24, B2O3 0-20, CaO 0-20, MgO+SrO+BaO+ZnO 0-4, Al2O3 0-5 and ZrO2+La2O3+Ta2O5+WO3 0-3, all being in % by weight, and having a refractive index (nd) of 1.58-1.65, an Abbe number ( gamma d) of 35-50 and a specific gravity of 2.69 or less. This optical glass is light in weight, high in transparency and low in dispersion, and is particularly suitable for spectacle lenses, but can also be utilized for photographic lenses.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. Optical lens of light-weight glass consisting essentially of the following composition in % by weight and having a refractive index (n d ) of 1.58 through 1.65, and Abbe number (ν d ) of 35 through 50 and a specific gravity of 2.69 or less: ______________________________________
SiO.sub.2 47-70
Li.sub.2 O 5.5-21
K.sub.2 O 2-30
Li.sub.2 O + K.sub.2 O
21-50
TiO.sub.2 9.5-24
CaO 0-20
MgO + SrO + BaO + ZnO 0-4
Al.sub.2 O.sub.3 0-5
ZrO.sub.2 + La.sub.2 O.sub.3 + Ta.sub.2 O.sub.5 + WO.sub.3
0-3.
______________________________________
2. The lens of claim 1, wherein the proportions of two of the components are as follows in % by weight, n d is within the range 1.58 through 1.64, ν d is within the range of 39 through 50 and specific gravity is 2.59 or less: ______________________________________
TiO.sub.2
9.5-20
CaO 0-4.
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